The present disclosure broadly relates to the art of spring devices.
Spring devices of the present disclosure find particular application and use in conjunction with suspension systems of wheeled vehicles, and will be described herein with specific reference thereto. However, spring devices of the present disclosure are also amenable to use in other applications and environments. Thus, it is to be understood that any applications and/or uses specifically shown, described or otherwise referred to herein are merely exemplary.
It is well known that land vehicles of most types and kinds are outfitted with a suspension system that supports a sprung mass (e.g., a body or chassis) of the vehicle on an unsprung mass (e.g., axles or wheel-engaging members) of the vehicle. It is also well known for some suspension systems to include gas spring devices that are operatively connected between the sprung and unsprung masses of the vehicle. Typically, such gas spring devices include two relatively rigid end members that are sealingly connected to respective open ends of a spring wall to at least partially form a spring chamber therebetween. The end members of such gas spring assemblies are often constructed of metal. However, in some constructions a substantially rigid plastic material has been used.
The spring wall is adapted to flex during dynamic operation and use of the gas spring device and is therefore normally made from a flexible, elastomeric material. During operation, the gas spring device is loaded such that opposing forces act against the end members. It is well recognized in the art that the spring wall does not itself support the load. Rather, the pressurized gas retained within the gas spring device by the spring wall acts against the end members and thereby provides forces capable of supporting loads applied to the end members.
To withstand the forces applied thereto by the aforementioned pressurized gas, conventional spring walls commonly include internal reinforcement that acts to buttress the elastomeric material of the spring wall and thereby help to restrict the expansion of the same, both under internal design pressures and under dynamic pressure levels associated with use under load. Such internal reinforcing structures typically include reinforcement filaments or cords that are embedded in the material from which the spring wall is constructed.
As discussed above, it is the pressurized gas within the gas spring device that supports any load acting thereon. Thus, it is normally desirable to retain the pressurized gas within the spring chamber and minimize pressurized gas losses such as, for example, may be due to the formation of exit pathways through which the pressurized gas can escape from the spring chamber. As such, most known gas spring constructions endeavor to provide a robust interconnection between the spring wall and the corresponding end structure or end member. Thus, even minor separations between the material of the spring wall and the end structure or end member are not normally expected to result in the formation of an exit pathway therebetween.
However, it has been recognized that the filament structure embedded within the spring wall can act as a network of small passageways disposed throughout the spring wall. Thus, pressurized gas from the spring chamber that is permitted to reach this network of small passageways may eventually find an exit path through which the pressurized gas can reach an environment external to the gas spring device. It has also been recognized that otherwise minor separations along the interface between the elastomeric material of the spring wall and the corresponding end structure or end member, while normally not sufficient to operate as an exit path by itself, can provide access for the pressurized gas to reach the filament structure of the spring wall and, thus, the network of small passageways formed thereby.
Accordingly, it is desirable to develop a spring wall and end structure connection and/or interface that overcomes the foregoing and other difficulties and/or disadvantages.